1. Field of the Invention
The present invention relates to an image display device and to a scanning circuit used in the image display device.
2. Description of the Related Art
There has been a voltage drop problem in some cases of drive of a semiconductor circuit with a low-resistance load due to the on resistance (Ron) of an output portion (output buffer) of the semiconductor circuit.
As a method of reducing the resistance of an output portion of a semiconductor circuit, the method of increasing the semiconductor chip area is known. For example, in the case of increasing the chip area of a MOS device having a high withstand voltage, it is necessary for the MOS device to have a double diffusion structure. In such a case, the area occupied by the chip is increased. That is, an area of about 1 mm2 is occupied in the case of obtaining an output on resistance (Ron) of 100 mΩ.
If a semiconductor integrated circuit having an 80-channel output portion is designed, an area of 80 mm2 is occupied by the output buffer alone. Further, a prebuffer is required for drive of the output buffer. In actuality, therefore, a chip area close to 100 mm2 is required for the output buffer alone.
Arts described below are known which relate to the invention of the present application.
JP-A 6-230338 A discloses an arrangement in which feedback control is performed to apply a bias voltage with stability to semiconductor devices for driving a liquid crystal display device.
JP-A 10-153759 A discloses a correction circuit in which dummy wiring is provided in parallel with scanning lines in a liquid crystal panel, a signal line drive current flowing through the dummy wiring is converted into a distortion voltage, and the difference between the distortion voltage and a reference voltage is fed back to a scanning line drive circuit to correct a distortion of the signal line drive voltage.
JP-A 5-212905 A discloses a device for forming an image with a printing head using an LED array and discloses, in particular, an arrangement in which a voltage detection resistor is connected in parallel with an LED array drive transistor to detect an abnormality of the printing head.